The present invention relates to a Medium Voltage distribution switchboard, having a high level of integration of functionalities.
In the present electrical energy distribution system architecture, the electrical switchboard acts as a node, while the cable and overhead lines represent the conjunction of the various nodes.
According to this scheme, within the switchboard are concentrated all the required system management functions that have to be dealt with for electrical energy distribution. These functions are historically divided into two different types, primary and secondary functions.
Primary functions are called all functions related to the main voltage, current and power distribution, while secondary functions are called all functions related to auxiliary and control features.
Some examples of primary functions are:
making, breaking, conduct the nominal current, withstand the short circuit current for a certain time, disconnection, earthing, connections and disconnections of cable for substitution or test, isolation of live part from operators.
Some secondary functions are: protection, interlocking, supervision (local or remote), control (local or remote), automation, measure, metering, diagnostic, communication.
All these functions are provided by means of switchboards composed of several functional units.
The different functions are subdivided among different components within the functional units of the switchboard, usually in the following way:                one or more metal enclosures are used to contain and confine the electrical equipment, isolating it from the operator, allowing in this way safe operation;        the switching units allow some of the primary functions like making, breaking and disconnections; in several occasions more than one switching or earthing unit is necessary per functional unit;        the Switchboard Control Unit (SCU) integrates many of the secondary functions, like measure, protection, control and communication;        Current and Voltage Transformers (CT, VT) are placed in a convenient position on the switchboard, taking into account that their size is usually relevant.        
All the above mentioned components are manufactured in a very industrialised way, with standard characteristic and properties demonstrated by specific performed type tests.
A number of further electrical and mechanical components are required in order to complete the switchboard, as shutters, contacts, busbars, withdrawable plugs, etc.
A large part of these components realize secondary functions: they are connected through a bundle of wires (intra-panel vertical cabling within the functional unit) and another bundle of wires connects each functional unit with the others of the same switchboard (inter-panel horizontal cabling within the switchboard).
Present solution in primary distribution single panel is reported in FIG. 2b, with relevant single line diagram in FIG. 2a. In FIG. 2b a withdrawable CB can be spring operated or magnetically actuated; in the second case (FIG. 2a) a control electronic (CE) and an energy storage capacitor (SC) is integrated on-board to control and supply the magnetic actuator (MA).
Voltage measure is an optional feature (in grey in FIG. 2a), usually required for busbar voltage measure in bus-tie CB and in incoming feeders.
Spreading the different functions among different components leads to a simplification in the objects themselves, but makes the system as a whole much more complex. This leads to wide space occupation and high costs, due to the presence of a lot of components, required cabling and wiring, and the necessity to develop an ad hoc design, at least for the secondary technique part, of the functional unit for each specific customer application.
In present solutions there are functional units including a switching device controlled by an Intelligent Electronic Device (IED), but such IED is only devoted to the switching device control and command and has no access to other information coming from other parts of the functional unit, for example the primary current and voltage values. Moreover in present solutions this IED is not committed to perform monitoring, control and protection functions that usually are assigned to a (functional unit) protection and control unit positioned in a separate compartment, i.e. the low voltage compartment. In this case the functional unit contains two separate IEDs that have to communicate and coordinate each other, for example remote operation commands arrive at the protection unit that has to re-send them to the switching device controller unit; this implies an added complexity and cost due to duplication of intelligence to perform functionalities that could be designed to be concentrated in a unique IED avoiding any problem of co-ordination and communication.